This invention relates to a device for clamping a support assembly, adjustably holding an arm in the support assembly and adjustably holding a table or other device by a swivel connection at the outer end of the arm.
It is known that an arm member may be held at an angle in a support assembly and that the support assembly may be clamped to a desk or other furniture. A small table may be positioned at the outer end of the arm and its angle may be adjusted relative to the arm.
In addition, there are various types of swivel connections shown in the patent literature. In U.S. Pat. No. 2,506,884 entitled "Camera Stand For Medical Photography" a swivel ball having a screw threaded post has a bore perpendicular to the post. A bolt passes through the bore and through opposite side supports to adjustably hold the ball. In U.S. Pat. No. 3,198,408 entitled "Support For A Manikin Form" a swivel ball is held between a fixed ring seat and a movable ring seat, the moveable ring seat being mounted on a screw operated plunger. Similarly in U.S. Pat. No. 3,211,405 a swivel ball is held between fixed and moveable rings, but the moveable ring is progressed by a cam device.
One problem with these prior swivel arrangements is that they require relatively heavy and expensive machined parts.
The present invention overcomes this difficulty by providing a swivel connection which uses relatively light weight and inexpensive sheet metal parts. Since the swivel connection is relatively light in weight, it may be mounted at the end of an arm, without requiring a heavy arm or a specially strong arm support assembly.
In accordance with the present invention, an arm member comprises, at its outer end, a U-shaped channel having a base and opposite extending side wall arms. A hole in the base forms a round rim. A ball protrudes through the rim and a post (boss) extends from the ball. The post is screw-threaded so that a small table or other device, such as a lamp, may be mounted thereon. A lever means within the channel applies pressure to the ball to retain it in position. The lever means is a sheet metal member one end of which is fixed to the channel member. The lever member has a round opening with a rim which bears against the ball.
An adjustment means extends from the arm member. Preferably, the adjustment means is a knob fixed to a threaded shaft. It is connected to the lever means and adjustably applies pressure to the ball, so that the ball may turn when the adjustment means is loosened and prevented from turning when it is tightened.
The present invention is particularly advantageous in supporting visual display units for computers. The swivel connection permits ready adjustment to each individual user's requirement.
The following detailed description describes a representative and presently preferred embodiment of the invention.